Method and apparatus for signaling and otherwise utilizing radiant impulses



R. A. FESSENDEN. METHOD AND APPARATUS FOR SIGNALING AND OTHERWISEUTILIZING RADIANT IMPULSES.

I APPLICATION FILED JAN. I4. I918. 1,384,014. Patented July 5, 1921.

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.R. A. FESSENDEN.

METHOD AND APPARATUS ,FOR SIGNALING AND OTHERWISE UTILIZING RADIANTIMPULSES.

APPLICATION FILED IAN. I4. I9I8.

1,884,014. Patented July 5, 1921.

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' pulses from the lamp 22onstriking the re-' flector 14 are reflectedtoward the direction UNITED STATES PATENT OFFICE.

REGINALD A. FESSENDEN, OF BROOKLINE; MASSACHUSETTS; ASSIGi-ITOB T0SUBMA- RINE SIGNAL COMPANY, .OF PORTLAND, MAINE, A CORPORATION OF MAINE.

METHOD AND APPARATUS FOR SIGNALING AND OTHERWISE UTILIZING RADIANTIMPULSES.

Application filed January 14, 1918.

To all whom it may concern:

Be it known that I, -REGINALD A. FEs- SENDEN, of Brookline, in thecounty of Norfolk and State (if Massachusetts, a citizen of the UnitedStates, have invented new and useful Improvements in Methods andApparatus for Signaling and Otherwise Utilizing Radiant Impulses, ofwhich the following is the specificationj My invention relates to theproduction and utilization of radiant impulses both in the ether and inmatter. For example, light waves, heat waves, ultra-violet waves, Xrays, Hertzian waves, sound waves, and the like. It relates moreespecially to signaling and detecting objects by radiant impulses andhas for its object increased efficiency in the utilization of radiantimpulses and more particularly increased efficiency insignaling anddetecting bodies by means of radiant impulses.

Figures 1 to 7 show, partly diagrammatically, apparatus adapted forcarrying out my invention.

In Fig. 1, 14 is a reflector for radiant impulses constructed in anysuitable way so as to reflect, in the direction from which they came,radiant impulses striking it, no matter, within certain limits, how thereflector may be tilted.

For example, in Fig. 4 the radiant imof the lamp, as shown in the dottedlines.

I accomplish this by arranging three reflecting surfaces 11, 12, and 13so that each is at right anglesto the other two; From this constructionI obtain the result that no matter how the reflector is tilted, so longas the radiant impulses enter the solid angle formed by the threereflecting surfaces 11,

12, and 13, the light or other radiant impulse is reflected back towardthe source.

The optical properties of such geometrical arrangement of planereflecting surfaces are easily established from long known optlcal lawsbut so far as can be ascertained have never been practically constructedor utilized, and in the absence of any naine for this arrangement'ofthree reflecting plane surfaces at right angles to each other it hasSpecification of Letters Patent.

Patented July 5, 1921.

Serial No. 211,758.

been called, as a matter of convenience, the reflector.

The linear dimensions of these reflectin surfaces are--.preferably largemultiples of thedwave length of the radiant impulses use Thesereflectingsurfaces 11, 12, 13 may consist of three mirrors, as shown infront view in 1 and in side view-in Fig. 2. For signaling purposes theyare preferably mounted as shown with a diagonal of one reflectingsurface 11 horizontal, though the exact arrangement is usually a matterof no importance.

The reflector 14, formed of the three reflecting surfaces 11', 12, 13 isconveniently attached to a rod 15. To this rod 15 is at? tached ashutter 16, as shown, operated in any convenient mannerfor example, by akey or aphotographic bulb release or, as

shown, by the string 45. 17 is a mirror attached to the sleeve 18 sothat it can be slid up and down the rod 15. When the mirror 17 is at anangle of approximately 45, it and the upper reflecting surface 11 form atrench perisco e so that an eye placed, as shown, at 46, i 2, will seeby reflection objects to the rig t as shown by the dotted lines. Theshutter 16 is omitted in Fig. 2 in order to show more clearly the use ofthe apparatus as a trench periscope for signal- 1ng.

Fig. 3 shows another form of reflector in which instead of using threeplane mirrors a tetrahedron consisting of the corner of a cube oftransparent material such as glass is used, 11, 12, and 13 being theportions of the sides of the cubes which meet to ether at one cornerandithese sides of the on e being silvered while the fourth side of thetetrahedron, facing the observer, as .shown in Fig. 3, ,is leftunsilvered. The silver coating is covered with some protecting material,such as cement, rubber, or metal.

The corner where the three sides 11, 12,

For example, it is more compact and the sides beinm once ground at theright an le the reflecting surfaces always maintain tiieir truerelation. Also there is some advantage when non-chromatic light is usedin that the color of the reflected light gives some indication of theway in which the reflector is held and somewhat widens the field.

The object of grinding off the corner 20 as shown in Fig. 3 andpolishing it, or in the case of the three mirror type drilling the hole20, as shown in Fig. 4, is so that the observer by placing his eye inthe position 46 may observe the signaling light 22.

Fig. 4 shows an arrangement of apparatus suitable for communicatingbetween the first line trenches and the rear trenches or between theadvance and the first line trenches.

During the present year, 1917, the official reports of the operations onthe west front are to the effect that the best method of signaling sofar found for the advance is the signaling lamp, substantially aheliograph using artificial instead of solar illumination. Theobjections to this, as stated in the official report, are that whenprovided with suflicient storage battery to last in case the ad- Vanceis cut off by barrage it is too heavy; also that the man carrying itcannot carry his rifle or anything else; also that there isoften'considerable difliculty in the advance signaler and rear signalergetting in touch with each. other, since both projecting lamps have tobe alined simultaneously.

The present invention overcomes these difficulties and has otheradvantages.

The method of using is shown inFig. 4. Here 21 is a shutter, 22 a sourceof light, 23 a reflector, v24: a telescope. These are used by the nalerto the rear, or in the case of advance} y the signaler in the trenches.14 is the reflector, 16 a shutter, 20 a hole bored at the corner of thereflecting planes, and 46' is the eye of the forward signaler. Thereflector is all that is carried by the forward signaler who, in anadvance, may be four or five miles in front of the trenches where therear observer is. 3

The operation is as follows: The front signaler goes forward equippedwith the reflector 14, and, as this weighs less than eight ounces,carrying his full equipment of rifle, etc. Suppose when he is a coupleof miles in advance it is desired to communicate with him. To do thisthe rear signaler swings his projlecting lamp 22, 23 over the terrain,keeping iis eye at the telescope 24:. As soon as the beam of theprojecting lamp strikes the reflector 14 the rear observer sees aflashand knows that the projecting beam .is in the right direction. Atthe same time the forward signaler with his eye at the point 46' seesthe flash from the projecting lamp. The rear signaler then by moving theshutter- 21 signals the call letter of the forward signaler sev raltimes and then leaves the shutter 21%4 {the open position. The forwardsi naleil ttiien moves the shutter 16 andcuts thebeam of light reflectedback to 24: and thus "gnals to the rear observer and communication isthus established.

In signaling at night time where it is not desired that the beam of theprojecting lamp 22, 23 should be seen by the enemy, in place of atungsten lamp 22 a source of ultraviolet radiation, such as a quartzmercury tube, may be used with a screen cutting off all visibleradiation, as is well known in the art, and the round corner 20 or theopposite face of the tetrahedron may be coated with a, florescentsubstance, such as sulfate of quinin, and also the object glass of thetelescope 24.

This method has the following advantages for signaling during anadvance:

(1) The whole apparatus carried by the advance signaler weighs less thaneight ounces and consequently he can carry his usual equipment.

(2) The apparatus cannot get out of order.

(3) It can be operated isolated from all supplies for any length of timeas it does not require fresh batteries, lamps, etc., to be brought upfrom the rear through territory exposed to shell fire.

(4:) The signaling range may be much greater than with projection lamps,as the only light source is operated from a fixed vance signaler.

(6) As the direction of reflection back is not influenced by thewabbling of the refector, the forward signaler does not have to stop inorder to receive messages from the rear signaler, and in fact by facingthe reflector toward the-rear and using the periscope mirror as shown inFigs. 1 and 2, he ma receive and transmit messages While wa king or evenwhile running forward.

(7) The forward signaler can operate his apparatus while protected inthe trench by sticking the pointed end 19 of the bar 15, Fig. 1, in theground so that only the reflector, a few inches square, projects abovethe trench.

(8) Itis easily manufactured and inexpensive.

For the above reasons, and others, it is extremely well adapted forsignaling during an advance and for other work, such as signalingbetween an artillery station and. an. 30

aeroplane and where ultra-violet light or infra-red light is used it hasthe additional advantage over wireless and other forms of signaling thatthe fact that signaling is going on is not disclosed to the enemy.

Applicant has discovered that infra-red radiation is especiallyadvantageous in that it is not affected by transmission through fog orsmoke to anything like the same extent to which ultra-violet radiationis affected.

Fig. 5 shows the application of the inven-- tion to marine work-in theease shown to a buoy marking the position of a channel. Here 25 is thebuoy having a number of these reflecting prisms 14, 14, 14, 14 of anykind of colored glass'desired arranged as a crown on the top of thebuoy.

A ship desiring to pick up the channel, on coming within three or fourmiles of the sup-posed entrance to the channel, swings its projectoraround the horizon. Immediately the projector beam is pointing in thedirection of the buoy the man standing beside the projector sees theanswering flash, since no matter how the buoy 25 is rocking or tiltingon the water the beam is always reflected toward the source, 11. 6.,toward the projector.

This method has the following advantages:

(1) The buoy may be picked up over a greater distance than a. light buoybecause the source of light 2'. 6., the arc lamp pro-' jector, of theship is a much more powerful source than the source of light installedon the light buoy.

(2) The buoy cannot be mistaken for shore lights or any light carryingobject.

(3) In time of war channels may be left marked with this type of buoybecause the only way in which an enemys shi could ick up the buoy wouldbe by using t is proector, in which case the enemys ship would beimmediately observed. a

(4) A ship icking up a buoy in this way does not disc ose the positionof the buoy to any other ship in the vicinity as the reflected beam issent back directly to the ship carryin the projector. 1

(5) arge and expensive buoys are not necessary as the apparatus willwork just as well when installed on an inexpensive spar buoy. v

(6) The cost of maintenance is practically nothing and there is nothingto get out of order as the prism crown can be protected by an irongrating.

Fig. 6 shows the apparatus applied to wireless telegraphy. In this caseonly one set of sending apparatus is necessary, as shown in the upperpart of Fig. 6.

Here 26, 27 are the radiating conductors, preferably dimensioned so asto radiate Hertzian waves of a few centimeters wave length. 28 is anoscillating audion, or pliotron,,pro-

ducing waves of a few centimeters wave length. 34 is a switch forsignaling and 2%) a. source of electric power for exciting the audion28. y The receiving apparatus is shown in the lower part of Fig. 6,where 30, 31 are the receiving conductors, 32 a wireless receivingapparatus of any suitable form, and 33 a double head telephone receiver.

14 is the reflector and 16 a "shutter, in the present case preferablymade of metal and slanted at an angle so that its plane is notperpendicular to the dotted lines showing the path of the Hertzianwaves.

The operation is similar to that of the optical apparatus shown in Fig.4.

Fig. 7 shows the apparatus arranged to operate with sound impulses ofvery short wave length.

The transmitting apparatus is shown in the upper part of Fig. 7 andconsists of a source of high frequency oscillations 35, which may be apliotron generator or, as shown, a high frequency dynamo giving say50,000 cycles per second. of the type described in applicants U. S.Patent 706,737, issued August 12. 1902.

36 is a transmitter to be used when the apparatus is used fortelephoning. 37 is a. key, kept closed when telephoning and operatedwhen the apparatus is used for telegrapliing. 39 is the source of sound,which may be an oscillator of the type shown in applicants U. S. Patent1,167,366, issued January 4, 1916, which has been found very suitablefor producing such high frequency mechanical vibrations, or a condenserof the type shown in applicants U. S. Patent 1,182,843, issued 1V ay 9,1916, Fig. 5, with the additional improvement, 2'. e. the local battery38, the addition of this local battery having been found to increase theefiiciency of the apparatus as a generator. 40 is a diaphragm, which maybe one plate of the condenser 29 or may be a separate plate of metal orother suitable material. The receiving apparatus is shown at the bottomof Fig. 7, where 42 is any suitable receiving apparatus, for example theoscillator above referred to, and 41 being either a plate of thecondenser or a separate diaphragm. 44 is the receiver, which may be ofany suitable typecapable of receiving high frequency electricalvibrations, and 43 is a local battery. 14 is the reflector and 16 is ashutter, as above.

The method of operation is as described with reference to Fig. 4.

These ultra-audible sound vibrations, called by the writer anacysms,have a number of advantages in that they can be projected as a welldefined beam of sound and can be used for secret sending and operated bythe heterodyne or similar apparatus.

Means for signaling by radiant impulses specification decomprising 'atetrahedron having three adjoining faces at right angles to each otherand a, surface in proximity to said tetrahedron whereby the incidence ofradiant energy on sald tetrahedron may be determined.

REGINALD A; FESSENDEN.

